Note: Mensa considers that scores from after January 31, 1994, "No longer correlate
with an IQ test."

I did these calculations using a method similar to that for my GRE to IQ Estimator. The lowest point of reference was the theoretical average IQ of high school students being 110 and the current average SAT I V+M (verbal + math) score being 1019. Everything below that is extrapolation. Also note that the decimal places give the impression that the numbers are more precise than they really are.